That actually makes a good point of showing why swearing during debate is counter productive.
It is unnecessary, it makes the person look immature, it distracts from the point they are trying to make.
And here's the thing, debate is not JUST about who is correct. Debate is an intercourse where you try to convince the other side of the debate believe that you are correct.
If you see someone claim that 1+1=3 and know that it is actually 2 then you are correct whether or not you start a debate with him. But if your argument is "Motherfucker ass cracker! It's bloody 2 you cocksucking abortion!" you are less likely to win them over.